Factors that contribute to the death/severity and onset of COVID-19 infection in working generation: Investigation of general health examination items by narrative review

The coronavirus disease 2019 (COVID-19) pandemic that affected Japan remains vivid in our collective memory. Currently classified as a Category 5 virus (for which medical institutions and individuals primarily implement preventive measures independently, without significant administrative intervention such as isolation), COVID-19 infections continue to peak biannually, currently driven by the Nimbus variant, a derivative of the Omicron strain. This situation necessitates ongoing vigilance in infection prevention efforts. While it is well-established that environmental factors, such as proper ventilation, are crucial in mitigating the risk of COVID-19 transmission, it has become evident that variations in individual susceptibility exist; some individuals contract the virus while others do not, even in identical environments. Personal factors, including pre-existing medical conditions, influence this disparity. This narrative review examines personal factors related to general health assessments within the workplace, incorporating data from systematic reviews and meta-analyses, as well as insights from both international and domestic academic societies. Although the strength of evidence varies, factors such as male gender, smoking, alcohol consumption, obesity, inadequate sleep, insufficient physical activity, hypertension, hyperlipidemia, diabetes, and chronic obstructive pulmonary disease have been identified as contributors to the severity and onset of COVID-19, as well as its associated mortality.